Early Bedtimes Linked to Increased Physical Activity, Study Finds

Research led by Monash University has revealed that individuals who retire early to bed tend to engage in higher levels of physical activity the following day. The findings, published in the Proceedings of the National Academy of Sciences, examined the relationship between sleep duration and timing in relation to next-day physical activity.

The study analyzed data from nearly 20,000 participants who wore a biometric device called WHOOP over the span of a year, generating close to six million nights of sleep data. This allowed researchers to gather objective metrics on both sleep and physical activity.

Results indicated a clear correlation between bedtime and levels of physical activity. Participants who typically went to bed around 9 PM reported approximately 30 minutes more of moderate-to-vigorous physical activity each day compared to those who regularly went to sleep at 1 AM. Even when compared with the average bedtime of 11 PM, those sleeping at 9 PM demonstrated nearly 15 additional minutes of daily physical activity.

Dr. Josh Leota, a researcher at Monash University, highlighted that individuals who favor later bedtimes might face disadvantages, especially within traditional work schedules. He noted that the conflict between natural sleep patterns and standard 9-to-5 work hours could lead to social jetlag, poor sleep quality, and increased fatigue during the day, all of which may hinder motivation for physical activity.

Crucially, the study also explored whether altering bedtimes could actively influence physical activity levels. It found that participants who went to sleep earlier than their usual time while maintaining their typical sleep duration exhibited the highest levels of physical activity the next day.

Dr. Leota emphasized the public health implications of these findings, suggesting that health initiatives should not only promote sleep and physical activity independently but also advocate for earlier bedtimes as a way to encourage more active lifestyles. He argued that a comprehensive approach that acknowledges the interplay between these two key behaviors could significantly enhance individual and community health outcomes.

An additional validation study involving approximately 6,000 participants from the All of Us Research Program, which utilized Fitbit data, corroborated these findings, indicating consistency across various demographic groups.

Dr. Elise Facer-Childs, a senior researcher at Monash University, remarked on the significant relationship between sleep timing and physical activity levels. She pointed out that while both sleep and physical activity are crucial for overall health, the connection between them had not been fully understood until now. The study's results suggest that individuals who manage to go to sleep earlier while keeping their sleep duration consistent are likely to increase their physical activity the next day.